Well, I'm not totally against the idea of this card. However, each element "has it's thing", or theme, right? Well, Life's theme is healing. Every other element that is given a powerful healing spell takes away and dilutes Life's theme. It's sort of like creating a darkness creature with immaterial. Should the idea be discarded right away? No. But it should have a harder time getting to the crucible, and alternatives should be discussed.
Now, to address your using other elements with healing...
Earth: Stoneskin. This isn't technically healing. You can't EM with Stoneskin alone, so it is slightly different.
Light: Miracle and Holy Light. Well, Miracle is really only useful for stalling. Again, it can't let you EM, and since it consumes all your remaining light quanta, it is used in different situations. Holy Light seems to be primarily a creature healing card.
Gravity: I know you didn't mention this, but Black Hole does technically heal. Like Holy Light, it has a significantly different function, quanta denial. The healing seems to be something of a side effect.
Now, back to this card. All of the previously mentioned cards either can't earn you an EM, or they're primarily used for something other than healing yourself. This card, however, has those uses, and those uses only. While Guolin's solution does seem OP(without tweeking, which I know he intended), it does stay within Water's theme.